Specific aim: To assess the importance of genetic, environmental and genetic-environmental interactions in the etiology of adult alcoholism. Alcohol problems and antisocial behavior problems will be the genetic factors. Social conditions in the adoptive home will be the environmental factors. Methodology: A sample of 200 adult adoptees aged 18-40, separated at birth from biologic parents and placed with nonrelatives will be given a structured psychiatric interview to detect alcohol abuse and dependency. One hunded adoptees (Group A) will be selected whose first-degree biologic relative has an alcohol problem. A control group (Group C) will be selected whose biologic relatives have no recorded psychopathology and will be matched to the A group individuals by age, sex, time spent in foster care, and by age of the biologic mother. Environmental factors will be assessed from a structured interview given adoptive parents and adoptees, and from information on labor, delivery, and neonatal development available in adoption records. The importance of genetic, environmental and gene-environment interaction factors will be determined from log-linear multivariate analyses. Long-term objectives: 1) Confirm previous finding of environmental factor of alcohol problem in adoptive family which predicted increased adoptee alcoholism and: (a) detail time course, amount of social contact, etc., of adoptee with individual with alcohol problem, and (b) explore hypothesis that adoptee's perceived attitude of significant others toward alcohol plays role in adoptee's own alcohol abuse or drinking pattern; 2) explore further other environmental factors which have come close to predicting significantly alcohol abuse, e.g., psychiatric problems (other than alcohol or antisocial) in adoptive family; 3) confirm previous suggestive findings of gene-environment interaction between factors of alcohol problem in first-degree relative and adoptive family with alcohol problem; 4) provide understanding of how adult alcoholism might arise from genetic and environmental factors and ultimately lead to rational alcoholism prevention by environmental manipulation.